<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title></title>
    <!-- 传统DOM操作 -->
</head>
<body>
    <div id="box"></div>
    <script>
        const msg='乌拉乌拉'
        // const ff = document.querySelector('div')
        const ff = document.querySelector('#box')
        ff.innerHTML=msg
        console.log(ff);
    </script>
</body>
</html>